GB1400031A - Power lift for a tractor - Google Patents

Abstract

1400031 Tractor power lift mechanism MASSEY-FERGUSON SERVICES NV 13 Oct 1972 [15 Oct 1971] 47259/72 Heading A1P A tractor power lift mechanism comprises a draft control operated via a link 65 with follow up provided by a member 37 and a link 69 and also a depth limiting linkage operated by a link 101 and is characterised in that the mechanism is in two portions, one carried by the main housing 15 and the other by the detachable part 17. The detachable part supports the valve V and bell cranks 43, 49, 107 and has access holes for adjustment of screws 105 and 54. The remainder of the mechanism is mounted in the main housing 15. The detachable part 17 can be removed by means of screws 20, for the purpose of, for instance, servicing. The mechanism is so arranged that separation and reassembly of the detachable part requires neither special disconnection beforehand nor readjustment afterwards of the linkage. Operation. In order to lower the draft linkage, link 65 is moved forwards to cause a shaft 61 and also a member 67 to rotate anticlockwise about the axis 59. This will cause rearward movement of a shaft 60, a sleeve 64 and a pin 58 and simultaneously urge a control rod 53 rearward through the spring 55. This motion is transmitted through a bell crank 49, a link 47 and a bell crank 43 to the valve operating rod 41, to urge the valve V against its spring into a position to allow the implement to lower. As the implement enters the ground, a draft sensing device causes the input member 37 to be moved downwards. This downward movement acts through the link 73 and lever 69 to rotate the shaft 64 counterclockwise, acting to relieve the force through a spring 55 on the member 53 to allow the valve V to close. When the draft force has increased to the figure preset by the link 65, then a member 37 will have moved downwards sufficiently to close off the valve V. A link 101 is set to a position representing the maximum depth to which the implement is required to go. This movement of link 101 acts through the links 99, 95, pin 93 and link 89 to locate the lower pin 90 of the floating lever 83. As the implement is lowered, the rock shaft 16 rotates clockwise causing a lever 85 to move forward. Through the intermediate pin 92, the extension 79 on the control rod 53 is moved rearward and when the maximum depth selected is reached the valve V will be closed off. In order to raise the implement out of the ground, the lever 65 is moved rearward to cause the shaft 61 to rotate clockwise which causes forward movement of the forked member 57, thereby moving the control rod 53 forward and through the bell crank 49, lever 47 and bell crank 43, permit the valve V to allow oil into the cylinder raising the implement. As the implement is raised, the rock shaft 16 rotates counter clockwise and when a maximum transport height is reached, the pin 109 engages the arm of the bell crank 107. This action urges the bell crank 43 to shut off the valve and hence to stop the raising of the implement.